Clean soil is rejuvenating New York’s urban farms

As Sara Perl Egendorf, a Ph.D. candidate in soil science at Brooklyn College, points out, building farms with new, clean soil provides all manner of ecosystem benefits to farms and gardens

By Lela Nargi
Salon
Sept 14, 2019

Excerpt:

New York’s community farms and gardens are planted in layers of purchased topsoil, or compost that can be procured free of cost from the city’s sanitation department. Each method has its drawbacks. Buying soil is expensive for budget-strapped gardeners, and “compost breaks down and oxidizes over time,” creating a need to eventually add more soil to a planting bed to keep it from eroding back to the lead-containing layer, Egendorf explains.

Back in 2013, NYC’s Mayor’s Office of Environmental Remediation (OER) was getting ready to open its Clean Soil Bank. The idea: to pass on some of the copious sediment excavated from building sites to local development projects, like filling street tree beds, rather than trucking it to distant landfills.

These sediments consist mostly of sand, silt, and clay and were deposited by glaciers that moved through the area over the last 2 million years. They lie under a crust of sometimes marginally contaminated material, and they’re often super pure, with only 10 parts per million (ppm) of lead or less — much less than the 400 ppm that start to raise health flags. Although this material doesn’t contain much in the way of nutrients, when mixed with organically rich compost it makes an excellent base for new soil.

Read the complete article here.